| 摘要 |
PURPOSE:To provide a method for producing fine particle powder in which the platy iron oxide fine particle powder having a fine surface diameter, especially below 0.5mum and a high flatness ratio (plate surface diameter/thickness), especially >=5 is industrially obtained. CONSTITUTION:An aqueous solution of a ferrous salt, an aqueous solution of an aluminum salt and an aqueous solution of carbonate are used and mixed while regulating the pH within the range of 8.0-11.0 to produce and precipitate platy hydrotalcite type fine particles. The resultant precipitate is then separated by filtration, washed with water and dried while taking over the particle shape of the platy hydrotalcite type fine particles. Thereby, the platy hydrotalcite type fine particles containing Fe ions and Al<3+> are obtained. The hydrotalcite type fine particles containing the Fe ions and Al<3+> are subsequently heated at 300-700 deg.C in air to afford platy hematite fine particles in which aluminum is converted into a solid solution. The resultant hematite fine particles are further thermally reduced to provide magnetite particles. |
